The documentstion states: "These routines return information about a single column of the current result row of a query." "The sqlite3_column_type() routine returns the datatype code for the initial data type of the result column. The returned value is one of SQLITE_INTEGER, SQLITE_FLOAT, SQLITE_TEXT, SQLITE_BLOB, or SQLITE_NULL. The return value of sqlite3_column_type() can be used to decide which of the first six interface should be used to extract the column value." If sqlite3_column_type returns SQLITE_NULL, then that column has the value NULL for the current row of the result set.